/*
 * @(#)ShellAlias.java	1.0 Apr 18, 2008
 *
 *	The MIT License
 *
 *	Copyright (c) 2008 Malachi de AElfweald <malachid@gmail.com>
 *
 *	Permission is hereby granted, free of charge, to any person obtaining a copy
 *	of this software and associated documentation files (the "Software"), to deal
 *	in the Software without restriction, including without limitation the rights
 *	to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 *	copies of the Software, and to permit persons to whom the Software is
 *	furnished to do so, subject to the following conditions:
 *
 *	The above copyright notice and this permission notice shall be included in
 *	all copies or substantial portions of the Software.
 *
 *	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 *	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 *	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 *	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 *	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 *	OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 *	THE SOFTWARE.
 */
package org.eoti.io.console.shell.cmd;

import org.eoti.io.console.shell.Shell;
import org.eoti.io.console.shell.ShellException;
import org.eoti.io.console.shell.ShellExtension;
import org.eoti.util.StringUtil;

import java.util.*;
import java.util.concurrent.*;

public class ShellAlias
	extends ShellExtension
{
	protected CopyOnWriteArrayList<AliasRedirect> aliases;

	public ShellAlias()
	{
		super();
		aliases = new CopyOnWriteArrayList<AliasRedirect>();
	}

	protected void computeFormat()
	{
		int col1 = 0;
		int col2 = 0;
		int col3 = 0;
		for(AliasRedirect alias : aliases)
		{
			col1 = Math.max(col1, alias.newCommand.length());
			col2 = Math.max(col2, alias.oldCommand.length());
		}
		if(col1 == 0 || col2 == 0)
		{
			setFormat("  %s:  %s  %s\n");
			return;
		}
		col3 = getConsoleWidth() - col1 - col2 - 7; // spaces and colons
		setFormat(
				"  " +
				defaultFormat(col1) +
				":  " +
				defaultFormat(col2) +
				"  " +
				defaultFormat(col3) +
				"\n"
		);
	}

	public void execute(List<String> arguments)
			throws ShellException
	{
		if(arguments.isEmpty())
		{
			computeFormat();
			for(AliasRedirect alias : aliases)
			{
				format(
						alias.newCommand,
						alias.oldCommand,
						StringUtil.join(alias.oldCommands, " ")
				);
			}

			shell.format("%s aliases found.\n", aliases.size());
			return;
		}

		String newCommand = arguments.remove(0);
		if(arguments.isEmpty()) // need to have an 'oldCommand' to map to
			error("Incorrect format.\n%s", getUsage());

		aliases.add(new AliasRedirect(shell, newCommand, arguments));
	}

	public String getName()
	{
		return "alias";
	}

	public String getUsage()
	{
		return "alias [new-command old-command [old-command-parameters...]]";
	}

	public void manual()
	{
		shell.format("ALIAS is design to make repeated instructions easier to manage.\n");
		shell.format("Instructions: %s\n\n", getUsage());
		shell.format("Example: alias dir ls\n");
		shell.format("This will make a new command 'dir' that works just like the command 'ls'.\n");
		shell.format("Just entering 'alias' will print out existing aliases.\n");
	}

	class AliasRedirect
			extends ShellExtension
	{
		protected String newCommand;
		protected String oldCommand;
		protected List<String> oldCommands;

		public AliasRedirect(Shell shell, String newCommand, List<String> oldCommands)
		{
			super();
			setShell(shell);
			this.newCommand = newCommand;
			this.oldCommands = oldCommands;
			this.oldCommand = oldCommands.remove(0);
			shell.register(this);
		}

		public void execute(List<String> arguments)
				throws ShellException
		{
			ArrayList<String> newCommands = new ArrayList<String>(oldCommands);
			newCommands.addAll(arguments);
			shell.getExtension(oldCommand).execute(newCommands);
		}

		public String getName()
		{
			return newCommand;
		}

		public String getUsage()
		{
			return String.format(
				"'%s' is an alias for '%s %s'.",
				newCommand,
				oldCommand,
				StringUtil.join(oldCommands, " ")
			);
		}

		public String getManual()
		{
			return getUsage();
		}
	}
}
